The proposed project will use a new application of phosphorescent materials as the reporter in a capture immunoassay for food-borne pathogens. These inorganic phosphors promise to increase the sensitivity of the assay thus allowing a faster and easier procedure. The phosphors have the unique property of absorbing infrared and emitting visible light (upconversion). Upconversion does not occur in biological molecules, therefore there is no interference with the signal. This, and other features of the phosphors provide a means of developing highly sensitive assays. This increased sensitivity will allow the elimination of the time-consuming culture step required with current methods. We propose to develop a model E-coli 0157:H7 assay, and a breadboard photometer to quantitate the signal. The advantages of this technology will be demonstrated by comparison with commercial, culture-dependent assays. The resulting technological innovation will have significant clinical and commercial potential. PROPOSED COMMERCIAL APPLICATION: Development of a phosphor based immunoassay system will permit increased sensitivity, will decrease testing time, and enable detection and measurement of organisms that are no longer viable. The new technology offers the opportunity to replace present assay methods, which require 18 to 24 hour incubation of the test sample for replication of the target organism. The markets where this technology can be used are the food testing industry which require rapid, highly sensitive and specific assays.